American law requires a voluntary act or omission before assigning criminal liability. The law also presumes that an individual who is unconscious, such as a sleepwalker, is incapable of a voluntary act. For some criminal defendants in the United States this all-or-nothing approach to the voluntary act requirement can mean the difference between unqualified acquittal if they are found to have acted involuntarily, lengthy institutionalization if they are found to be insane, and incarceration or even the death penalty if their acts are found to be voluntary. In contrast to the law’s dual dichotomies of voluntary/involuntary and conscious/unconscious, modern neuroscientific research indicates that the boundaries between our conscious and unconscious states are permeable, dynamic, and interactive. To enable the law to join science in a more nuanced and just view of the human mind, this article proposes that, in addition to voluntary and involuntary acts, the criminal law recognize a third category - semi-voluntary acts.

The idea seems sensible that certain acts currently called "unconscious," like acts during sleepwalking, might profitably be subject to some state intervention short of an insanity commitment, even if retributive instincts about what justifies criminal punishment cannot be met.